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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Meeting Today’s Exploration and Development Challenges with Wide Azimuth Seismic Acquisition

Funmi R. Ebiwonjumi1; Zuwena Rawahi1; Cees van Eden1; Mohammed Mazrui1; Martin Healey2

(1) Exploration, Petroleum Development Oman LLC, Muscat, Oman.

(2) Development, Petroleum Development Oman LLC, Muscat, Oman.

Recent challenges in the global economy call for efficiency in all aspects of the oil and gas exploration and exploitation processes. The South Oman Salt Basin comprises of over 7 km basin fill complex with a mix of clastics, carbonates and evaporites deposited over a period of 600 million years. The prospective sequence of isolated Ara carbonate stringers occurs near the base of the mobile Ara Gp evaporates that constitute the main structural control on both intra-salt and post-salt deposits. The area lacked good quality seismic data for consistent interpretation of the self-sourced Ara carbonate stringers. The low confidence in seismic picks, culminating into broad depth uncertainty ranges, in prospecting for the sometimes tectonically altered stringers necessitated a new fit-for-purpose seismic. The recent acquisition of wide azimuth (WAZ) seismic data over the greater Birba area brought relief in exploring and developing the Ara play. By deploying receivers over a large area (8 x 12 km), the WAZ geometry allows sampling of the complete wave-front reflected from the subsurface. This improvement comes with the associated challenge of multi-data cube interpretation, huge IT infrastructure requirements and the need for 24 hours operations. Evaluation of the WAZ seismic (first delivery) showed improvement in ease of interpretation (loop definition and continuity), better structural definition, enhanced attributes (frequency and amplitude) and improved well-to-seismic matches. This implies a more consistent interpretation of Top Salt with the added value of an improved depth conversion of the intra-salt carbonate stringers. The new WAZ seismic data increased the confidence in the exploration and development evaluation of the Ara stringer play. The improved subsurface imaging will improve our subsurface de-risking efficiency.